The present invention relates to gas turbine compressors and in particular to turbojet engine compressors.
More specifically, it relates to an axial compressor stator comprising a rigid, external annular frame and axially juxtaposed rings which are configured radially inside the frame and which support stationary annuli of vanes running radially inward, these annuli including arcuate segments affixed to the frame by appropriate fastening means and externally defining the compressed-gasses' aerodynamic conduit.
In general the arcuate segments comprise an inside wall bounding the aerodynamic conduit and radial ribs pointing outward and resting against the external annular frame, the ribs configured with bases to affix by means of bolts the arcuate segments on the frame. The stationary vanes are affixed in an orifice in the inner wall.
The compressed gases of a turbojet engine high-pressure compressor are hot. The inside walls of the arcuate segments are in direct contact with the hot gases and therefore expand, providing additional play between rotor and stator. Conductive heat transfer by means of the ribs and bolts takes place between the inside wall and the annular frame. The rise in frame temperature entails an increase in displacement directly affecting the play between rotor and stator. The conventional remedy includes cooling the assembly by tapping a cooler gas flow from a region upstream of the compressor, which results, however, in an overall degradation of gas turbine engine efficiency.